Field of the Invention
The present invention relates to a stent implanted and used in the bile duct or the pancreatic duct.
Description of the Related Art
In the related art, with respect to a narrow portion formed in the bile duct or the pancreatic duct, implantation of the stent is performed in order to expand the narrow portion and to maintain a patency state.
For example, a stent disclosed in Japanese Unexamined Patent Application, First Publication No. H06-7453 is known. The stent is formed of polyethylene having radiolucency. The stent has a front end and a front end excretion hole, and has a base end blade section and a base end excretion hole (a second opening section) in the vicinity of a base end of the stent. When the stent is disposed in the bile duct, as a front end of a base end blade section is hooked by the duodenal papilla, the base end portion of the stent protrudes from the duodenal papilla into the lumen of the duodenum to be implanted therein. As the stent is implanted into the bile duct, excretion of the bile from the bile duct to the small intestine through the common bile pipe (an internal space) and the duodenal papilla is promoted.